W波段三倍频器的设计与仿真

分析了平衡倍频器的工作原理和结构,并使用商用肖特基势垒二极管DBES105a设计一个W波段宽带三倍频器。电路采用微带线制作,并安装在波导中。倍频器电路的波导微带过渡结构、低通滤波器和匹配枝节均使用电磁场分析软件HFSS仿真。最后在ADS中利用谐波平衡法对倍频器电路进行优化。仿真结果表明,当输入功率为20 dBm时,在80 GHz～100 GHz范围内,输出功率十分平稳,约为5 dBm。     

W频段宽带倍频器

介绍了一个W频段宽带倍频器.采用反向并联二极管对结构实现宽带倍频.该倍频器输入为WR-28波导到微带过渡结构,输出为WR-10减高波导.在输入功率为5dBm时,在整个W频段输出功率为0.81±1.80dBm,二次谐波抑制度大于25dBc.该倍频器可把Ka频段的信号源扩展到W频段.     

毫米波宽带二倍频器设计

基于鳍线/悬置微带线耦合器提出了一种适用于毫米波变容二极管的宽带平衡式二倍频器结构。鳍线作为二极管对的驱动输入端,同时提供直流偏置接地。二极管对的直流偏置电压由输出悬置微带/WR-22波导转换的探针馈入。结合宽带输入WR-42波导/鳍线转换、宽带鳍线/悬置微带线耦合器以及宽带悬置微带线/WR-22波导转换实现了覆盖整个Q频段的平衡式二倍频器。在输入功率为+20dBm,变容管反偏置电压1.2V时,输出33～50GHz的范围内倍频效率大于10%。     

D频段新型二倍频器设计

利用阻性二极管实现了一种D频段二倍频器,设计了一种新型双鳍线输入过渡结构,并成功应用于该二倍频器,该结构能更好地实现输入波导与二极管的匹配.该二倍频器采用肖特基势垒二极管MA4E2038,电路制作在0.05 mm厚石英基片上.仿真结果表明,在146.8 GHz处获得最高倍频效率10.3％.实物测试结果显示,在自偏置情况下倍频器在148 GHz处获得最高倍频效率2.3％,在0.7V偏置电压下倍频器在154 GHz处获得最大输出功率1.1 mW.输出功率可以满足多数应用下对信号源的需求,该倍频器对处于大气窗口的140GHz通信系统具有借鉴作用.     

亚毫米波二倍频器的设计

亚毫米波在电磁波频谱中占有很特殊的位置,因此,在学术上有很重要的学术价值,但目前在国内对亚毫米波倍频源的研究还寥寥无几。建立了电路拓扑结构。器件以串联的方式安装于输入波导与悬置微带线连接处的混合结上,可满足偶次倍频的要求。通过ADS和HFSS等软件的联合仿真设计出180 GHz平衡式无源二倍频器,并对二倍频器电路进行了加工、制作和测试。     

3 mm二倍频器的设计与实现

设计了一种W波段二倍频器,输入为46～48 GHz,输出为92～96 GHz,用来为毫米波接收前端系统提供3 mm本振信号.二倍频器采用微带线制作,且输入和输出端口位于腔体轴向两侧,选择对脊鳍线过渡来完成波导-微带的过渡结构.采用电磁场电路设计软件ADS,大大提高了毫米波电路设计的效率和准确度.测试结果表明,在输出92～96 GHz频带范围内,倍频损耗在22 dB以内.基波和三次谐波的抑制大于24 dB.该二倍频器符合工程使用的标准,同时其设计过程也表明了计算机辅助设计在毫米波电路设计方面是非常有价值的,可以大大提高工作效率.     

无基片空间合成的220 GHz三次倍频电路研究

基于四阳极结同向串联型GaAs平面肖特基二极管,设计并实现了无基片空间合成的220 GHz三次倍频电路。采用四支肖特基二极管协同工作,在脊波导小片上下两侧各倒装焊接两支肖特基二极管,构成上下反向结构。采用场路结合的方式,对倍频电路的倍频效率进行了仿真。仿真结果显示输入功率为300 mW,输出频率为213~229 GHz时,倍频效率大于3%;采用E波段功率放大器推动三次倍频电路,获得了倍频器输出功率。测试数据表明,驱动功率为300 mW时,输出频率为213~229 GHz时,输出功率大于5 dBm,倍频效率为1%~2%。     

单片集成430 GHz三倍频器的设计及测试

通过单片集成的方法,将工作于太赫兹频段(430GHz)的三倍频器的各个功能电路集成在厚度为12μm的砷化镓薄膜单片上,设计、制造太赫兹三倍频集成电路单片。单片结构采用一对反向并联连接的肖特基二极管,构成串联平衡式电路,电路不需要外加偏置电压。平衡式电路只产生奇数次谐波,简化了电路分析和优化过程。电路设计采用三维电磁仿真软件与谐波非线性仿真软件联合仿真场路的方法,准确模拟单片电路的射频特性。将单片电路安装在中间剖开的波导腔体内制成三倍频器进行测试,在430GHz处测得输出功率为215.7μW,效率为4.3%。     

基于平面肖特基二极管的220 GHz二倍频器

介绍了一个基于平面肖特基二极管的220 GHz倍频器。该倍频器工作在室温下,结构简单。为了实现倍频,将一个具有4个反向串联肖特基结的变容二极管安置在石英基片上,直流偏置通过一个石英微带构成的低通滤波器加到二极管上。所有的石英电路基片都用导电胶粘接在波导腔体上,波导腔体是E面剖分的,表面镀金。220 GHz倍频器的测试结果表明,在选择合适的偏置电阻时,该倍频器具有15 mW的输出功率和5%的效率。在213~230 GHz频段,二倍频器的输出功率均在10 mW以上,且带内的功率波动非常小。     

Q波段宽带功率合成倍频器的设计北大核心CSCD

提出了一款输出频率覆盖整个Q波段的高功率固态有源四倍频器模块。倍频器基于混合集成电路技术实现,采用有源二倍频—功率放大—功率分配—无源二倍频—功率合成的拓扑结构。在前级采用基于悬置带线的180°反相器进行功分器设计,以实现宽带性能以及结构紧凑性。在无源二倍频时,采用两个分立的MA4E1310肖特基二极管组成非平衡倍频结构获取其二次谐波,并通过波导双探针进行合成输出,以此突破单个二极管的功率容量制约,进而提高倍频输出功率。测试结果表明,固态倍频源模块在5.5 V/0.9 A的直流偏置以及5 dBm的输入功率下,可以在33~50 GHz全波导频率范围内获得15~19 dBm的输出功率。     

Development of the readout system for waveguide multilayer optical card

Waveguide multilayer optical card （WMOC） is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling ＆ processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic （VB） language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.     

Nanoimprint Lithography -A Next Generation High Volume Lithography Technique

IntroductionNanoimprint Lithography is a well-acknowl-edged low cost, high resolution, large area pattern-ing process. It includes the most promising methods,high-pressure hot embossing lithography (HEL) [2],UV-cured imprinting (UV-NIL) [3] and micro contactprinting (m-CP, MCP) [4]. Curing of the imprintedstructures is either done by subsequent UV-lightexposure in the case of UV-NIL or by cooling downbelow the glass transition temperature of the ther-moplastic material in case of HEL…     

Collinear phase-matching study of terahertz-wave generation via difference frequency mixed in GaAs and Inp

The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.     

Effects of the alloy compositions on the phonon-polaritons in ternary mixed crystals

Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.     

Influence of PVK ： NPB hole transporting layer on the characteristics of organic light-emitting devices

A doping system consisting of NPB and PVK is employed as a composite hole transporting layer （CHTL）. By adjusting the component ratio of the doping system, a series of devices with different concentration proportion of PVK ： NPB are constracted. The result shows that doping concentration of NPB enhances the competence of hole transporting ability, and modifies the recombination region of charge as well as affects the surface morphology of doped film. Optimum device with a maximum brightness of 7852 cd/m^2 and a power efficiency of 1.75 lm/W has been obtained by choosing a concentration proportion of PVK ： NPB at 1：3.     

New insert layer structure OLEDs

An insert layer structure organic electroluminescent device（OLED） based on a new luminescent material （Zn（salen）） is fabricated. The configuration of the device is ITO/CuPc/NPD/Zn（salen）/Liq/LiF/A1/CuPc/NPD/Zn（salen）/Liq/LiF/A1. Effective insert electrode layers comprising LiF（1nm）/Al（5 nm） are used as a single semitransparent mirror, and bilayer cathode LiF（1 nm）/A1（100 nm） is used as a reflecting mirror. The two mirrors form a Fabry-Perot microcavity and two emissive units. The maximum brightness and luminous efficiency reach 674 cd/m^2 and 2.652 cd/A, respectively, which are 2.1 and 3.7 times higher than the conventional device, respectively. The superior brightness and luminous efficiency over conventional single-unit devices are attributed to microcavity effect.     

Analysis of error performance on Turbo coded FDPIM

Due to variable symbol length of digital pulse interval modulation（DPIM）, it is difficult to analyze the error performances of Turbo coded DPIM. To solve this problem, a fixed-length digital pulse interval modulation（FDPIM） method is provided. The FDPIM modulation structure is introduced. The packet error rates of uncoded FDPIM are analyzed and compared with that of DPIM. Bit error rates of Turbo coded FDPIM are simulated based on three kinds of analytical models under weak turbulence channel. The results show that packet error rate of uncoded FDPIM is inferior to that of uncoded DPIM. However, FDPIM is easy to be implemented and easy to be combined, with Turbo code for soft-decision because of its fixed length. Besides, the introduction of Turbo code in this modulation can decrease the average power about 10 dBm, which means that it can improve the error performance of the system effectively.     

A method for calculating the center position of collimated light

It is a key problem to accurately calculate beam spots＇ center of measuring the warp by using a collimated laser. A new method, named double geometrical center method （DGCM）, is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device （CCD） is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What＇s more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.